*{
    margin: 0;
    padding: 0;
}

body{
    height: 100%;
    background-color: #505f6e;
}

#game{
    width: 100%;
    background-color: #505f6e;
}

#topBox{
    width: 100%;
    height: 100px;
    position: fixed;
    top:0;
    background-color: #505f6e;
    z-index: -999;
}

header{
    margin: 0 auto;
    text-align:center;
    user-select: none;
}

header h1{
    font-size: 50px;
    font-weight: bold;
    color: white;
}

header button{
    margin:2% 0;
    padding:10px 10px;

    font-size: 20px;
    font-family: Arial sans-serif;
    color:white;
    background-color: #3e4e5f;

    border:none;
    border-radius: 10px;
    outline:none;

    transition: scale 1s;
}
header button:link{}
header button:visited{}
header button:hover{transform: scale(1.1);}
header button:active{background-color: #5b6f86;
}

header p{
    color: white;
    font-family: "微软雅黑 Light", "等线 Light", sans-serif;
    font-size: 20px;
}

#box{
    height:500px;
    width: 500px;
    padding:10px;
    margin:0 auto;
    background-color: #405161;
    border-radius: 10px;
    position: relative;
    user-select: none;
}

.cell{
    width: 100px;
    height: 100px;
    display: inline-block;
    background-color: #606e7b;
    border-radius: 6px;
    position: absolute;
}

.number-cell{
    width: 0;
    height: 0;
    border-radius: 5px;
    position: absolute;
    font:bold 0/100px 'Arial' ;
    text-align: center;
    z-index: 0;
}

footer{
    padding: 5% 10% 0;
}

footer address{
    text-align: center;
    margin: 5% 10% 0;
    bottom: 0;
}

@media screen and (min-width:900px)
{
    footer{
        padding-top: 0;
    }
    footer br{
        display: none;
    }
    footer h6,p{
        padding: 0;
    }
    footer address{
        margin: 0;
    }
}